1. The Circulatory System
Blood, Blood Vessels and the Heart

2. C5: 5 types of Blood Vessels
a. arteries
b. arterioles
c. veins
d. venules
e. capillaries

4. Arteries
Have thick, muscular walls so they are able to withstand the blood pressure coming from the heart
Carry blood AWAY from the heart
Elastic: handle change in blood volume after each ventricular contraction

5. Arterioles Small arteries are called ARTERIOLES
Not as elastic as arteries
They relax causing the arteriole to dilate, resulting in the opposite effect: increase blood volume, decrease pressure

6. Veins Carry blood TOWARDS heart Have a thin muscle layer
Contain VALVES to help the blood return to the heart
Small veins are called venules

7. Valves in Veins
there is not enough blood pressure to make the blood return all the way to the heart
One-way valves and the skeletal muscles work together to squish the blood back heart

9. Varicose Veins
If the valves malfunction in the legs, a painful condition can result
Called Varicose veins
Allows blood to pool in the elastic veins, causing them to bulge

12. Varicose veins in rectum are called hemorrhoids.

13. Capillaries Connect the veins and arteries
Site of gas exchange between blood and cells
Oxygen, nutrients and water diffuse out of the blood and into the cells
Carbon dioxide, wastes and water diffuse out of the cells and into the blood

14. Capillaries have extremely thin walls for diffusion.

15. Comparison of Blood vessels
Most of the bp that came from the heart is lost when the blood travels through the capillaries
That is why you need VALVES in your veins.

18. C3: Your Heart – structure and function
Mostly Muscle
Beats about times per minute
Is comparable to two pumps joined together
Has 4 chambers:
Right Atrium, right ventricle
Left Atrium, Left Ventricle

19. Anatomy diagrams are labelled as if you are looking down on a patient (unless otherwise indicated)
Therefore, the R.A. is the patient’s right – not yours!

20. PIG HEART

21. Structure of the Heart 4 One-Way-Valves
between the atria and the ventricles on both sides = Atrioventricular valves
at the exit of both ventricles = semi-lunar valves
prevent blood from flowing backwards
If one of your valves is defective, you might have a “heart murmur”.

22. 
Top View (looking down)

25. Chordae Tendineae
Anchor AV valves on ventricles to prevent valves from inverting

26. Chordae Tendineae

27. Demonstrate the flow of blood from the aorta through the body and back to the left ventricle.
good overview of circulation through heart, nodal control

28. Flow of Blood through the heart

29. Blood enters the R.atrium via the superior and inferior vena cava
When the Atria contract, blood moves from the R.A. to the R.Ventricle, passing the AV valve as it goes

30. The ventricles contract, and force the blood through the semi-lunar valve and out to the body via the AORTA
Blood Flow Video

31. Both atria fill and contract at the same time.
Both ventricles will fill and contract at the same time

32. The first heart sound, “lub” occurs when the AV valves close
The first heart sound, “lub” occurs when the AV valves close. The second heart sound “dub” occurs when the other valves close.

33. distinguish between systolic and diastolic pressures
When the cardiac muscle contracts it is called Systole
When the chamber relaxes it is called diastole

34. the SA node, AV node, and Purkinje fibres
·  Our heartbeat is INTRINSIC.
·  SPECIAL TISSUE, called NODAL TISSUE, has characteristics of both nerve and muscle tissue, controls the heartbeat.
There are TWO nodal regions in the heart:

35. 1. SA (sinoatrial) NODE SA Node
Located upper back wall of right atrium.
INITIATES THE HEARTBEAT every 0.85 seconds to make the ATRIA CONTRACT.

36. The SA node is called the “PACEMAKER” because it keeps the beat regular.
ARTIFICIAL PACEMAKERs, will send out an electric signal every 0.85 seconds to stabilize the heart rate if the SA node doesn’t work.

38. 2. AV (atrioventricular) NODE:
Located base of the R.A. near the septum.
When the pulse from SA Node reaches AV node, the AV node will send out a signal along conducting fibers called PURKINJE FIBERS. They take the message to the VENTRICLES, and cause them to contract.
The contraction of the ventricles begins at the base of the heart and moves up like a wave.
SA Node
AV Node
Purkinje Fibers

39. Video Clip

40. autonomic regulation of the heartbeat
Heart under involuntary control by the brain MEDULLA OBLANGATA,
This center can increase or decrease the heart rate
Various factors, such as stress, oxygen levels, and bp determine how the ANS will affect heart rate.
autonomic regulation of the heartbeat

41. distinguish between pulmonary and systemic circulation
Heart Beat
Heart in a Box

42. Flow of Blood: Blood travels in 2 loops
A. The Pulmonary system
- goes from the heart to the lungs and back to the heart again

43. Only place where deoxygenated blood is in ARTERIES, and oxygenated blood is in VEINS
Superior Vena Cava
Pulmonary artery
Aorta
Pulmonary Vein
Inferior Vena Cava

44. Review

45. b. Systemic Circuit
When L. ventricle pumps to push the blood to rest of body
This ensures there is ample blood pressure for the blood to deliver it’s oxygen and nutrients to the cells

47. The Coronary Arteries
The heart does not use the blood inside the atria or ventricles to get it’s nutrients and oxygen
Has own set of arteries and veins to supply oxygen and nutrients = coronary arteries

48. Circulatory Review
Circulatory rap

49. Atherosclerosis
Excess fat and cholesterol stick to the arteries, forming a PLAQUE
Plugs up the arteries, restricting blood flow
If the blood flow that is restricted is to the heart, a heart attack may occur

50. Angioplasty – possible procedure if the blockage isn’t too severe

52. Heart Attack When the cells of the heart do not get enough oxygen
The severity of the attack depends on how bad the coronary artery blockage is, and how many heart cells die
At first, the victim may suffer angina pectoris (radiating pain in the left arm).

53. One cause of heart attack:
Smoking
Nicotine causes heart to pump faster
Also causes some arteries to contract (get smaller)
Puts unneeded strain on the heart muscle

54. ·      Coronary Bypass Surgery: segments of leg veins are grafted between the aorta and coronary vessels, in order to bypass a blockage. Two to four such bypasses may be performed in a single operation. e.g. three such grafts would be known as a “triple-bypass” operation.
·      Coronary bypass, donor heart transplants, and artificial heart implantation (which don’t work yet!) are surgical methods that have been used for the treatment of heart attacks.
·      More than 50% of all deaths in Canada & U.S. are due to hypertension (high blood pressure), stroke, and heart attack.

55. Heart Attack: when portion of heart dies due to lack of oxygen
Heart Attack: when portion of heart dies due to lack of oxygen. At first, the victim may suffer angina pectoris (radiating pain in the left arm). Death may result if immediate treatment not given.

56. Some more nasty circulatory events:
Thrombus: a stationary clot attached to an arterial wall. Slows the flow of blood.
Embolus: a thrombus that has become dislodged and moves along with the blood. When the vessel narrows, the embolus gets stuck and entirely blocks the flow of blood in a small vessel. This is called an embolism.

57. Stroke: when portion of brain dies due to lack of oxygen -- usually when arteriole bursts or is blocked by an embolism. Strokes usually cause death or paralysis.